Anyway, I don't know if I have much more to contribute that others haven't already, but for our raid the difficulty of bosses was sort of divided into tiers, with the earlier names being generally easier, but are all around the same difficulty level, and the big jumps being between tiers.

First Tier -
Jin'Rokh
Ji'Kun
Iron Qon
Horridon

Second Tier -
Tortos
Council
Twins

Third Tier -
Primordius
Megaera
Durumu

Final Tier -
Dark Animus
Lei Shen
Ra-Den (Well, you can't take him til you take Lei Shen!)

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Also should note that everyone seems to put Tortos as really easy but for some reason he gave our raid ridiculous fits. Like, both Council and Twins went much easier than Tortos for us, and even Primordius, while having higher numbers, took WAY less suffering than Tortos originally did. YMMV

tortos is easy with throughput healers. If you run holy pally disc priest you're going to have a bad time.

We're kind of in the same boat. And we wiped for 2 1/2 hours again on Jin'rokh. I'm getting tired of people tunneling numbers and being bad.

Are you me? We too had like 2 hour wipefest last Wednesday because our ele shammy couldn't move out of the puddle when she got Focused Lightning. She blamed addons but why would they suddenly stop working if there was no patch.

Looks like we are the only one having a VERY bad time on Iron Qon. 120 wipes and counting... with horridon and Jikun easily on farm.
Next week we are going to try something else (tortosa and council I guess), if we are not calling for the summer.